***Microbiology Chapter 14***

STUDY

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Which of the following statements concerning pathology, infection, and disease is true?

Pathology refers to the study of structural and functional changes that occur in the body as a result of a disease.

Which of the following is an example of the symbiotic relationship known as mutualism?

E. coli within the large intestine

Koch's postulates established criteria for proving that a specific organism causes a specific disease. Which of the following is NOT one of the criteria given by Koch's postulates?

The pathogen must be isolated from inoculated animals and must be different from the original organism.

Which of the following is classified as a latent disease?

shingles

A patient acquires an infection by touching a contaminated door handle. Which mode of transmission best describes this scenario?

indirect contact transmission

A dog develops a diarrheal disease after drinking water from a creek during a hike with his owner. Which of the following best describes this method of disease transmission?

vehicle transmission

Plague is transmitted through the bite of an infected flea. Which of the following best describes this mode of transmission?

vector transmission

Which of the following is a fungal zoonosis that can be transmitted by direct contact?

ringworm

Which of the following would be an example of disease transmission via INDIRECT contact?

A student sneezes on her test booklet. The instructor grades it and catches her cold.

According to the animation, surgical infections account for what percentage of nosocomial infections?

20%

What type of nosocomial infection is likely to arise from intravenous catheterizations?

Bacteremia

How might a patient who is not being treated with an antibiotic still be exposed to an antibiotic?

Antibiotics can be used in aerosols, thereby entering the environment.

Why are invasive procedures likely to increase the risk of nosocomial infections?

These procedures allow microbes from the skin to enter the bloodstream of the patient.

How can health care workers reduce the occurrence of nosocomial infections?

Practice more stringent aseptic techniques

The health of the patient

should be the primary concern of the healthcare worker.

How can surgeons help to limit nosocomial infections?

They should perform surgeries and invasive procedures only when absolutely necessary.

If a patient notices a healthcare worker not following suggested precautions

they should immediately bring it to the attention of the healthcare worker.

Which of the following characteristics of a catheter should be considered, to help minimize the spread of nosocomial infections?

Single-use

Which of the following statements is true regarding hand washing?

Frequent and proper hand washing should be routinely done by patients and by healthcare workers, both prior to and after interaction.

Epidemiology is defined as the study of

where and when a disease occurs, and how it is transmitted.

What is the role of epidemiology?

To learn how to treat and prevent various diseases.

Expected prevalence of a disease is

the expected occurrence of a disease based on past observations.

In the sixth segment of the animation, why is the disease epidemic in North America?

The disease occurs at a higher rate than what would normally be expected in this region.

If a disease occurs at a fairly stable rate, it is said to be

endemic

Which of the following would be considered a fomite?

An infected toy

Which of the following would be considered a vector?

A fly carrying disease from fecal matter to food

When aerosols containing pathogens spread disease from a distance of less than one meter, it is considered

contact transmission.

Which of the following is considered a major category of transmission of disease?

Contact, vehicle, and vector transmission

Which is an example of vehicle disease transmission?

The presence of Listeria on undercooked chicken served for dinner

The following choices list several types of diseases, along with factors that may contribute to their emergence. Which disease and associated factor do NOT match?

emergence of avian influenza A (H5N1): use of antibiotics

As a health care worker, I am keenly aware of how important it is to avoid harming my patients. I worry about inadvertently transmitting an infectious disease to an already compromised individual. According to the CDC, what is the MOST important thing I can do to avoid this?

Wash my hands before interacting with any patient.

Which of the following statements about the development of infectious diseases is correct?

The period of convalescence is the time during which the person regains health and fully recovers (back to the pre-disease state).

Malaria is an infectious disease caused by infection with a protozoan. In certain tropical regions, malaria is constantly present. We would say that malaria is a(n) _________ disease in these regions.

endemic

One effect of washing regularly with antibacterial agents is the removal of normal microbiota. This can result in

increased susceptibility to disease.

During a six-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever 39°C lasting >2 days with three or more symptoms (i.e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years.

The etiologic agent of the disease in the situation is

Coxiella burnetii.

A commensal bacterium

may also be an opportunistic pathogen.

Which of the following statements is TRUE?

At least one member must benefit in a symbiotic relationship.

Transient microbiota differ from normal microbiota in that transient microbiota

are present for a relatively short time.

Which of the following is NOT an example of microbial antagonism?

bacteria causing disease

The yeast Candida albicans does not normally cause disease because of ______.

the normal microbiota

The major significance of Robert Koch's work is that

microorganisms cause disease.

Koch observed Bacillus anthracis multiplying in the blood of cattle. What is this condition called?

septicemia

Which of the following is NOT a verified exception in the use of Kochs postulates?

Some diseases are noncommunicable.

Which of the following definitions is INCORRECT?

epidemic: a disease that is endemic across the world

Focal infections initially start out as

local infections.

The rise in herd immunity amongst a population can directly attributed to

vaccinations

Which of the following is NOT a communicable diseases?

tetanus

Symptoms of disease differ from signs of disease in that symptoms

Which of the following definitions is INCORRECT?

A disease in which the causative agent remains inactive for a time before producing symptoms is referred to as

latent

The graph in the figure shows the incidence of polio in the United States. The period between 1945 and 1955 indicates a(n)

epidemic level.

Which of the following is NOT a predisposing factor of disease?

None of the answers are correct; all of these are predisposing factors of disease.

In which of the following diseases can gender be considered a viable predisposing factor?

urinary tract infections

In which of the following patterns of disease does the patient experience no signs or symptoms?

incubation and convalescence

If a prodromal period exists for a certain disease, it should occur prior to

illness

Which of the following diseases is NOT spread by droplet infection?

botulism

Biological transmission differs from mechanical transmission in that biological transmission

involves specific diseases.

Which of the following is NOT a reservoir of infection?

None of the answers is correct; all of these can be reservoirs of infection.

Which of the following is a fomite?

a hypodermic needle

Which of the following statements about biological transmission is FALSE?

Houseflies are an important vector.

Which of the following pairs is mismatched?

None of the pairs is mismatched.

A cold transmitted by a facial tissue is an example of which form of disease transmission?

vehicle transmission

A needlestick is an example of

fomite

During a six-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever 39°C lasting >2 days with three or more symptoms (i.e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years.

the situation is an example of

a zoonosis.

During a six-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever 39°C lasting >2 days with three or more symptoms (i.e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years.

The method of transmission of the disease in the situation was

vehicle.

Which one of the following is NOT a zoonosis?

None of the answers is correct; all of these are zoonoses.

A nosocomial infection is

acquired during the course of hospitalization.

Which one of the following does NOT contribute to the incidence of nosocomial infections?

gram-negative cell walls

Which of the following statements about nosocomial infections is FALSE?

The patient was infected before hospitalization.

Which of the following can contribute to postoperative infections?

All of the answers are correct.

Pseudomonas bacteria colonized the bile duct of a patient following his liver transplant surgery. This is an example of a

nosocomial infection.

Which of the following does NOT contribute to the emergence of infectious diseases?

The emergence of infectious diseases can be attributed to all of these

Which of the following statements is FALSE?

The M in MRSA stands for mannitol.

The science that deals with when diseases occur and how they are transmitted is called

epidemiology.

The CDC is located in

Atlanta, GA.

Which of the following best describes why West Nile Virus is considered to be an emerging infectious disease?

West Nile virus outbreaks have increased in number and affected areas since 1937.

During his research on West Nile virus, Bill learned that this virus is placed within a functional grouping known as arboviruses. What is meant by the term arbovirus?

Arboviruses get their name because they are typically arthropod-borne viruses that remain in nature because of biological transmission between susceptible hosts by blood-feeding arthropods, such as mosquitoes.

If mosquitoes are the mode of transmission for West Nile virus, why did the students in Bill's virology class focus on finding the virus in the dead birds rather than collecting mosquitoes to examine?

The students tried to isolate and identify West Nile virus from birds because they are an amplifying host for the virus, making it more likely that the virus can be isolated from these animals.

The brain tissue of the birds indicated the possibility of encephalitis. What is encephalitis, and why should this type of infection cause concern among health care professionals?

Encephalitis is an inflammation of the brain tissue. It is a concern to health care professionals because an infection in the brain means the virus has breached protective measures.

Which of the following is the best mode of controlling the spread of West Nile infections?

Limit exposure to mosquitoes to prevent the transmission of West Nile virus.

What features of West Nile virus make it an emerging disease of special concern?

Emerging infectious diseases are defined as ones that are new or changing, have increased in incidence in the recent past, or show a potential to increase in the near future. Given the increase in number of cases of West Nile virus encephalitis and avian death since it appeared in New York City in 1999, this virus meets the definition of an emerging infectious disease. Over half of known emerging infectious diseases are zoonotic, mainly of viral origin, and are likely to be vector-borne. West Nile virus is all of these things, and infections with this virus must be reported to the CDC for tracking. The CDC works along with the National Institutes of Health (NIH) and the World Health Organization (WHO) to address issues related to emerging infectious diseases. Together, these agencies have set goals for investigating, monitoring, and controlling emerging infectious diseases worldwide.